Don’t take any BS from them. They extended my hire car for more than that. I also reasoned with them that it took DL an unreasonable amount of time to make the decision to write the car off too. Accident happened 29th Oct they finally made the decision and gave me permission to order a replacement over Christmas.
If they don’t budge try going to your MP too. The amount of profit they make the least they can do is fully look after us, good luck with it.